Hello, I create a bukkit plugin, and I have problem with parametr, like Birch Wood, or Potion of Strength
ItemStack doesn't have a single set of arguments, don't you have an IDE ? Your IDE should list all available constructors with their arguments, just read them... Or see the JavaDoc: http://jd.bukkit.org/rb/apidocs/org/bukkit/inventory/ItemStack.html
feaq16 Try reading ? I've given you a link that lists available arguments, I really don't know what you want...
The data/damage/durability value of the item, a number casted to short (e.g. (short)5 ) But if you don't need it, don't write it... there are other constructors that don't require it.